Substrate processing apparatus and method of manufacturing semiconductor device

ABSTRACT

Substrate processing uniformity is improved in the surfaces of wafers and between the wafers. A method of manufacturing a semiconductor device, including: loading a substrate holder into an inner tube, the substrate holder holding a plurality of substrates in a state where the plurality of substrates are horizontally oriented and stacked; forming thin films on the plurality of substrates by supplying a source gas to an inside of the inner tube; and unloading the substrate holder from the inner tube, wherein the forming the thin films is performed in a state where a conductance of a space between an inner wall of the inner tube and a gas penetration preventing cylinder is smaller than a conductance of a region where the plurality of substrates are stacked.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

The present application is a Continuation application of applicationSer. No. 12/510,572, filed Jul. 28, 2009; which claims priority under 35U.S.C. §119 of Japanese Patent Application No. 2008-196562, filed onJul. 30, 2008, in the Japanese Patent Office, the entire contents ofwhich are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate processing apparatusconfigured to process a substrate and a method of manufacturing asemiconductor device.

2. Description of the Prior Art

In the related art, for example, as a manufacturing process of asemiconductor device such as a dynamic random access memory (DRAM), asubstrate processing process for forming a thin film on a substrate isperformed. Such a substrate processing process has been performed byusing a substrate processing apparatus, which includes a substrateholder configured to hold a plurality of substrates in a state where thesubstrates are stacked in a horizontal position, an inner tubeconfigured to accommodate the substrate holder, an outer tube configuredto enclose the inner tube, a source gas supply unit configured to supplya source gas such as a film-forming gas or oxidation gas to the insideof the inner tube, and an exhaust unit configured to exhaust gas from aspace between the outer and inner tubes so as to create a gas flowinside the inner tube. A film-forming gas or oxidation gas ishorizontally supplied between substrates loaded in the inner tube.

However, in the related-art substrate processing apparatus, the velocityof source gas supplied to the center part of a surface of an upper orlower substrate among a plurality of substrates held in the substrateholder is relatively lowered, and thus the uniformity of substrateprocessing can be deteriorated at the substrate or between substrates.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a substrate processingapparatus configured to prevent the velocity of supplied source gas fromdecreasing at the center surface parts of substrates held at upper orlower positions of a substrate holder in which a plurality of substratesare held, so as to improve the uniformity of substrate processingquality in the surfaces of the substrates and between the substrates,and a method of manufacturing a semiconductor device.

According to an aspect of the present invention, there is provided amethod of manufacturing a semiconductor device, the method including:loading a substrate holder into an inner tube, the substrate holderholding a plurality of substrates in a state where the plurality ofsubstrates are horizontally oriented and stacked; forming thin films onthe plurality of substrates by supplying a source gas to an inside ofthe inner tube; and unloading the substrate holder from the inner tube,wherein the forming the thin films is performed in a state where aconductance of a space between an inner wall of the inner tube and a gaspenetration preventing cylinder is smaller than a conductance of aregion where the plurality of substrates are stacked.

According to another aspect of the present invention, there is provideda method of manufacturing a semiconductor device, the method including:loading a substrate holder into an inner tube, the substrate holderholding a plurality of substrates in a state where the plurality ofsubstrates are horizontally oriented and stacked; forming thin films onthe plurality of substrates by supplying a source gas to an inside ofthe inner tube; and unloading the substrate holder from the inner tube,wherein the forming the thin films is performed in a state where adistance of an outer edge of the plurality of substrates accommodated inthe inner tube and a gas exhaust outlet is greater than a distancebetween the outer edge of the plurality of substrates accommodated inthe inner tube and a gas injection hole.

According to still another aspect of the present invention, there isprovided a method of manufacturing a semiconductor device, the methodincluding: loading a substrate holder into an inner tube, the substrateholder holding a plurality of substrates in a state where the pluralityof substrates are horizontally oriented and stacked; forming thin filmson the plurality of substrates by supplying a source gas to an inside ofthe inner tube; and unloading the substrate holder from the inner tube,wherein the forming the thin films is performed in a state where adistance between an upper end plate and a top plate of the inner tube isshorter than a distance between the plurality of substrates.

According to still another aspect of the present invention, there isprovided a method of manufacturing a semiconductor device, the methodincluding: loading a substrate holder into an inner tube, the substrateholder holding a plurality of substrates in a state where the pluralityof substrates are horizontally oriented and stacked; forming thin filmson the plurality of substrates by supplying a source gas to an inside ofthe inner tube; and unloading the substrate holder from the inner tube,wherein the forming the thin films is performed in a state where aconductance of a space between an inner wall of the inner tube and a gaspenetration preventing cylinder is smaller than a conductance of aregion where the plurality of substrates are stacked, and in a statewhere a distance of an outer edge of the plurality of substratesaccommodated in the inner tube and a gas exhaust outlet is greater thana distance between the outer edge of the plurality of substratesaccommodated in the inner tube and a gas injection hole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a substrate processing apparatusrelevant to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view illustrating a process furnaceprovided in the substrate processing apparatus relevant to the firstembodiment of the present invention.

FIG. 3 illustrates a modification version of the process furnace of thesubstrate processing apparatus relevant to the first embodiment of thepresent invention.

FIG. 4 is a vertical sectional view illustrating a process furnaceprovided in a substrate processing apparatus relevant to a secondembodiment of the present invention.

FIG. 5 is a cross sectional view illustrating a process tube provided inthe substrate processing apparatus relevant to the first embodiment ofthe present invention.

FIG. 6 is a perspective view illustrating an inner tube provided in thesubstrate processing apparatus relevant to the first embodiment of thepresent invention.

FIG. 7 illustrates a modification version of the inner tube of thesubstrate processing apparatus relevant to the first embodiment of thepresent invention.

FIG. 8 is a perspective view illustrating a boat provided in thesubstrate processing apparatus relevant to the first embodiment of thepresent invention.

FIG. 9 is a flowchart for explaining a substrate processing processrelevant to the first embodiment of the present invention.

FIG. 10 is a flowchart for explaining a substrate processing processrelevant to the second embodiment of the present invention.

FIG. 11 is a gas supply sequence diagram of a film-forming processrelevant to the first embodiment of the present invention.

FIG. 12 is a gas supply sequence diagram of a cleaning process relevantto the second embodiment of the present invention.

FIG. 13 is a table showing exemplary process conditions of afilm-forming process relevant to the first embodiment of the presentinvention.

FIG. 14 is a table showing exemplary process conditions of a cleaningprocess relevant to the second embodiment of the present invention.

FIG. 15 is a graph showing measured velocities of gas supplied to thecenter parts of surfaces of wafers.

FIG. 16A is a schematic view illustrating positions of etching residuesremaining in a conventional substrate processing apparatus.

FIG. 16B is a graph showing temperature distribution at the positions ofetching residues.

FIG. 17 is a vertical sectional view illustrating a process furnaceprovided in a conventional substrate processing apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment ofthe Present Invention

A first embodiment of the present invention will be describedhereinafter with reference to the attached drawings.

FIG. 1 is a schematic view illustrating a substrate processing apparatusrelevant to a first embodiment of the present invention. FIG. 2 is avertical sectional view illustrating a process furnace provided in thesubstrate processing apparatus relevant to the first embodiment of thepresent invention. FIG. 3 illustrates a modification version of theprocess furnace of the substrate processing apparatus relevant to thefirst embodiment of the present invention. FIG. 5 is a cross sectionalview illustrating a process tube provided in the substrate processingapparatus relevant to the first embodiment of the present invention.FIG. 6 is a perspective view illustrating an inner tube provided in thesubstrate processing apparatus relevant to the first embodiment of thepresent invention, in which gas exhaust outlets have a hole shape. FIG.7 illustrates a modification version of the inner tube of the substrateprocessing apparatus relevant to the first embodiment of the presentinvention. FIG. 8 is a perspective view illustrating a boat provided inthe substrate processing apparatus relevant to the first embodiment ofthe present invention. FIG. 9 is a flowchart for explaining a substrateprocessing process relevant to the first embodiment of the presentinvention. FIG. 11 is a gas supply sequence diagram of a film-formingprocess relevant to the first embodiment of the present invention. FIG.13 is a table showing exemplary process conditions of a film-formingprocess relevant to the first embodiment of the present invention.

(1) Structure of Substrate Processing Apparatus

First, an exemplary structure of a substrate processing apparatus 101relevant to an embodiment of the present invention will be describedwith reference to FIG. 1.

As shown in FIG. 1, the substrate processing apparatus 101 relevant tothe current embodiment includes a housing 111. To carry wafers(substrates) 200 made of a material such as silicon into and out of thehousing 111, a cassette 110 is used as a wafer carrier (substratecontainer) configured to accommodate a plurality of wafers 200. At thefront side (right in the drawing) inside the housing 111, a cassettestate (a substrate container stage) 114 is installed. The cassette 110is configured such that the cassette 110 is placed on the cassette stage114 and carried away from the cassette stage 114 to the outside of thehousing 111 by an in-process carrying device (not shown).

The cassette 110 is placed on the cassette stage 114 by the in-processcarrying device in a manner that wafers 200 are vertically positionedinside the cassette 110 and a wafer port of the cassette 110 facesupward. The cassette stage 114 is configured to rotate the cassette 110by 90 degrees vertically toward the backside of the housing 111 so as toplace the wafers 200 horizontally inside the cassette 110 and point thewafer port of the cassette 110 toward the backside of the housing 111.

Near the center part of the inside of the housing 111 in a front-reardirection, a cassette shelf (substrate container placement shelf) 105 isinstalled. The cassette shelf 105 is configured such that a plurality ofcassettes 110 can be stored in multiple rows and columns. A transfershelf 123 is installed at the cassette shelf 105 to place a cassette 110to be carried by a wafer transfer mechanism 125 (described later). Abovethe cassette stage 114, a standby cassette shelf 107 is installed forstoring cassettes 110 preliminarily.

Between the cassette stage 114 and the cassette shelf 105, a cassettecarrying device (substrate container carrying device) 118 is installed.The cassette carrying device 118 includes a cassette elevator (substratecontainer elevating mechanism) 118 a capable of moving upward anddownward while holding a cassette 110, and a cassette carrying mechanism(substrate container carrying mechanism) 118 b capable of movinghorizontally while holding the cassette 110. By associated operations ofthe cassette elevator 118 a and the cassette carrying mechanism 118 b,the cassette 110 can be carried among the cassette stage 114, thecassette shelf 105, the standby shelf 107, and the transfer shelf 123.

At the rear side of the cassette shelf 105, the wafer transfer mechanism(substrate transfer mechanism) 125 is installed. The wafer transfermechanism 125 includes a wafer transfer device (substrate transferdevice) 125 a capable of rotating or straightly moving a wafer 200 on ahorizontal plane, and a wafer transfer device elevator (substratetransfer device elevator) 125 b configured to move the wafer transferdevice 125 a upward and downward. The wafer transfer device 125 aincludes a tweezers (substrate transfer jig) 125 c configured to hold awafer 200 horizontally. By associated operations of the wafer transferdevice 125 a and the wafer transfer device elevator 125 b, a wafer 200can be picked up from an cassette 110 placed on the transfer shelf 123and charged into a boat (substrate holder) 217 (described later), or thewafer 200 can be discharged from the boat 217 and put into the cassette110 placed on the transfer shelf 123.

At the rear upper side of the housing 111, a process furnace 202 isinstalled. An opening (furnace port) is formed at the lower end of theprocess furnace 202, and a furnace port shutter (furnace portopening/closing mechanism) 147 is used to open and close the opening.The structure of the process furnace 202 will be described later.

At the lower side of the process furnace 202, a boat elevator (substrateholder elevating mechanism) 115 is installed as an elevating mechanismfor moving the boat 217 upward/downward to load/unload the boat 217into/from the inside of the process furnace 202. At an elevator base ofthe boat elevator 115, an arm 128 is installed as a connection tool. Onthe arm 128, the boat 217 is vertically supported, and a disk-shapedseal cap 219 is horizontally installed as a cover body for air-tightlysealing the lower end of the process furnace 202 when the boat elevator115 is lifted.

The boat 217 includes a plurality of holding members and is configuredto hold a plurality of wafers 200 (for example, about fifty to about onehundred fifty wafers) in a state where the wafers 200 are horizontallypositioned and vertically stacked (arranged) in multiple stages with thecenters of the wafers 200 being aligned. The structure of the boat 217will be described later in more detail.

Above the cassette shelf 105, a cleaning unit 134 a including a supplyfan and a dust filter is installed. The cleaning unit 134 a isconfigured to circulate clean air inside the housing 111 as a cleanedatmosphere.

In addition, at the left end side of the housing 111 opposite to thewafer transfer device elevator 125 b and the boat elevator 115, acleaning unit (not shown) including a supply fan and a dust filter isinstalled. Clean air drawn through the cleaning unit (not shown) flowsaround the wafer transfer device 125 a and the boat 217, and then theclean air is sucked by an elevator device (not shown) and discharged tothe outside of the housing 111.

(2) Operation of Substrate Processing Apparatus

Next, an operation of the substrate processing apparatus 101 relevant tothe current embodiment will be explained.

First, a cassette 110 is placed on the cassette stage 114 by thein-process carrying device (not shown) in a manner that wafers 200 arevertically positioned inside the cassette 110 and the wafer port of thecassette 110 faces upward. Next, the cassette 110 is vertically rotatedby the cassette stage 114 by 90 degrees toward the rear side of thehousing 111. 0 the wafers 200 are horizontally positioned inside thecassette 110, and the wafer port of the cassette 110 faces the rear sideof the housing 111.

By the cassette carrying device 118, the cassette 110 is automaticallycarried and temporarily stored to a predetermined position of thecassette shelf 105 or the standby shelf 107 and is then transferred tothe transfer shelf 123 from the cassette shelf 105 or the standby shelf107, or the cassette 110 is directly carried to the transfer shelf 123.

After the cassette 110 is transferred to the transfer shelf 123, a wafer200 is picked up from the cassette 110 by the tweezers 125 c of thewafer transfer device 125 a through the wafer port of the cassette 110,and the wafer 200 is charged into the boat 217 disposed at the rear sideof a transfer chamber by consecutive operations of the wafer transferdevice 125 a and the wafer transfer device elevator 125 b. After thewafer transfer mechanism 125 charges the wafer 200 into the boat 217,the wafer transfer mechanism 125 returns to the cassette 110 forcharging the next wafer 200 into the boat 217.

After a predetermined number of wafers 200 are charged in the boat 217,the lower end of the process furnace 202 closed by the furnace portshutter 147 is opened by moving the furnace port shutter 147. Next, theseal cap 219 is lifted by the boat elevator 115 so that the boat 217where a group of wafers 200 are held can be loaded into the processfurnace 202. After the boat 217 is loaded, a predetermined process isperformed on the wafers 200 inside the process furnace 202. Such aprocess will be described later. After the process, the wafers 200 andthe cassette 110 are carried to the outside of the housing 111 in areverse order to the above-described order.

(3) Structure of Process Furnace

Next, the process furnace 202 relevant to an embodiment of the presentinvention will be explained with reference to FIG. 2, FIG. 3, and FIG. 5to FIG. 8.

(Process Chamber)

The process furnace 202 relevant to an embodiment of the presentinvention includes a process tube 205 as a reaction tube, and a manifold209. The manifold 209 includes an inner tube 204 configured toaccommodate the boat 217 (described later), and an outer tube 203configured to enclose the inner tube 204. Each of the inner tube 204 andthe outer tube 203 is made of a heat-resistant nonmetallic material suchas quartz (SiO₂) and silicon carbide (SiC), and has a cylindrical shapewith a closed top side and an opened bottom side. The manifold 209 ismade of a metallic material such as SUS (stainless steels prescribed inthe Japanese Industrial standard) and has a cylindrical shape withopened top and bottom sides. The inner tube 204 and the outer tube 203are vertically supported from their bottom sides by the manifold 209.The inner tube 204, the outer tube 203, and the manifold 209 are coaxialwith one another. The bottom side (furnace port) of the manifold 209 isconfigured to be air-tightly closed by the seal cap 219 when the boatelevator 115 is lifted. Between the manifold 209 and the inner tube 204,a sealing member (not shown) such as an O-ring is installed to seal theinside of the inner tube 204 air-tightly. Inside the inner tube 204, aprocess chamber 201 is formed to process wafers 200.

Around the process tube 205 (the outer tube 203), a heater 207 isinstalled coaxially with the process tube 205 as a heating unit. Theheater 207 has a cylindrical shape and is vertically installed in amanner that the heater 207 is supported on a heater base (not shown)used as a holding plate. At the outer lateral and top sides of theheater 207, an insulating material 207 a is disposed.

(Substrate Holder)

The boat 217, which is a substrate holder configured to hold a pluralityof wafers 200 in a state where the wafers 200 are stacked in ahorizontal position, is inserted in the inner tube 204 (the processchamber 201) from the bottom side of the inner tube 204.

The boat 217, which is used as a substrate holder, includes a pair ofupper and lower end plates 217 c and 217 d and a plurality of posts 217a (for example, three posts) vertically installed between the upper andlower end plates 217 c and 217 d. A plurality of holding grooves 217 bare formed in each of the posts 217 a in a manner that the grooves 217 bare arranged at regular intervals in the length direction of the post217 a. The posts 217 a are oriented such that the holding grooves 217 bof the posts 217 a face each other. By inserting peripheral parts of thewafers 200 into the holding grooves 217 b that face each other, thewafers 200 (for example, about fifty to about one hundred fifty wafers)can be held in a state where the wafers 200 are substantially horizontalin orientation and are stacked at predetermined intervals (substratepitch intervals).

The periphery of a region of the boat 217 lower than a region of theboat 217 where the wafers 200 are stacked (where the holding grooves 217b are formed) is enclosed by a cylindrical gas penetration preventingcylinder 217 f. Top and bottom openings of the gas penetrationpreventing cylinder 217 f are air-tightly closed by a cover plate 217 eand the end plate 217 d, respectively. At the lower side of a sidewallof the gas penetration preventing cylinder 217 f, at least one vent hole217 g is formed.

Each of the end plate 217 c, the end plate 217 d, the post 217 a, thegas penetration preventing cylinder 217 f, and the cover plate 217 e aremade of a heat-resistant nonmetallic material such as quartz and siliconcarbide.

In a state where the boat 217 is accommodated in the inner tube 204, atleast a part of the gas penetration preventing cylinder 217 f is locatedlower than a heating region of the heater 207. That is, when the insideof the process tube 205 is heated by the heater 207, the temperature ofat least a part of a lateral side of the gas penetration preventingcylinder 217 f is lower than the temperature of a region where thewafers 200 are stacked.

Furthermore, in a state where the boat 217 is accommodated in the innertube 204, the distance between the upper end plate 217 c and a top plateof the inner tube 204 is shorter than, for example, the distance (stackpitch) between the stacked wafers 200. That is, the conductance of aspace between the upper end plate 217 c and the top plate of the innertube 204 is smaller than the conductance of a region where the wafers200 are stacked, and a gas flow is not easily created at the spacebetween the upper end plate 217 c and the top plate of the inner tube204.

Furthermore, in a state where the boat 217 is accommodated in the innertube 204, the distance between the inner wall of the inner tube 204 andthe gas penetration preventing cylinder 217 f is shorter than, forexample, the distance between the stacked wafers 200. That is, theconductance of a space between the inner wall of the inner tube 204 andthe gas penetration preventing cylinder 217 f is smaller than theconductance of a region where the wafers 200 are stacked, and a gas flowis not easily created at the space between the inner wall of the innertube 204 and the gas penetration preventing cylinder 217 f.

The lower side of the boat 217 is supported by a rotation shaft 255. Therotation shaft 255 is installed through a center part of the seal cap219. At the lower side of the seal cap 219, a rotary mechanism 267 isinstalled to rotate the rotation shaft 255. By rotating the rotationshaft 255 using the rotary mechanism 267, the boat 217 in which aplurality of wafers 200 are charged can be rotated inside the inner tube204.

The gas penetration preventing cylinder 217 f relevant to the presentinvention is not limited to the above-described structure.

For example, as shown in FIG. 3, by previously evacuating the inside ofthe gas penetration preventing cylinder 217 f when the top and bottomopenings of the gas penetration preventing cylinder 217 f areair-tightly closed by the cover plate 217 e and the end plate 217 d, thegas penetration preventing cylinder 217 f can be configured as a vacuumcap. In this case, a vent hole 217 g is not formed in any of thesidewall of the gas penetration preventing cylinder 217 f, the coverplate 217 e, and the end plate 217 d.

(Gas Nozzle)

At the sidewall of the inner tube 204, a preliminary chamber 201 a isinstalled along the stacked direction (vertical direction) of the wafers200 in a manner that the preliminary chamber 201 a protrudes outwardfrom the sidewall of the inner tube 204 in the radial direction of theinner tube 204 (toward the sidewall of the outer tube 203). A barrierwall is not installed between the preliminary chamber 201 a and theprocess chamber 201, and the inside of the preliminary chamber 201 acommunicates with the inside of the process chamber 201, such that gascan flow between the insides of the preliminary chamber 201 a and theprocess chamber 201.

Inside the preliminary chamber 201 a, a vaporized gas nozzle 233 a and areaction gas nozzle 233 b are installed along the circumferentialdirection of the inner tube 204 as a first gas nozzle and a second gasnozzle, respectively. Each of the vaporized gas nozzle 233 a and thereaction gas nozzle 233 b has an L-shape with vertical and horizontalparts. The vertical parts of the vaporized gas nozzle 233 a and thereaction gas nozzle 233 b are installed (extended) inside thepreliminary chamber 201 a along the stacked direction of the wafers 200.The horizontal parts of the vaporized gas nozzle 233 a and the reactiongas nozzle 233 b are installed through the sidewall of the manifold 209.

At lateral surfaces of the vertical parts of the vaporized gas nozzle233 a and the reaction gas nozzle 233 b, a plurality of vaporized gasinjection holes 248 a and a plurality of reaction gas injection holes248 b are formed along the stacked direction of the wafers 200,respectively. Therefore, the vaporized gas injection holes 248 a and thereaction gas injection holes 248 b are located at positions spacedoutward from the sidewall of the inner tube 204 in the radial directionof the inner tube 204. The vaporized gas injection holes 248 a and thereaction gas injection holes 248 b are formed at positions (heights)corresponding to the plurality of wafers 200, respectively. The sizes ofthe vaporized gas injection holes 248 a and the reaction gas injectionholes 248 b can be properly adjusted to obtain adequate gas flowrate andvelocity distributions inside the inner tube 204. For example, the sizesof the vaporized gas injection holes 248 a and the reaction gasinjection holes 248 b may be adjusted to be uniform or graduallyincreased from the lower side to the upper side.

The present invention is not limited to the case where the preliminarychamber 201 a is installed at the inner tube 204. For example, thepreliminary chamber 201 a may not be installed at the inner tube 204,and the vaporized gas nozzle 233 a and the reaction gas nozzle 233 b maybe directly installed inside the inner tube 204.

(Vaporized Gas Supply Unit)

To a horizontal end (upstream side) of the vaporized gas nozzle 233 awhich protrudes from the sidewall of the manifold 209, a vaporized gassupply pipe 240 a is connected. A vaporizer 260 is connected to anupstream side of the vaporized gas supply pipe 240 a for vaporizing aliquid source to generate a vaporized gas as a first source gas. Anon-off valve 241 a is installed at the vaporized gas supply pipe 240 a.Vaporized gas can be supplied from the vaporizer 260 to the inside ofthe inner tube 204 through the vaporized gas nozzle 233 a by opening theon-off valve 241 a.

Downstream sides of a liquid source supply pipe 240 c and a carrier gassupply pipe 240 f are connected to the upstream side of the vaporizer260 for supplying a liquid source and a carrier gas to the inside of thevaporizer 260, respectively.

A liquid source supply tank 266, in which a liquid source such astetrakis-ethylmethylaminozirconium (TEMAZr) is stored, is connected tothe upstream side of the liquid source supply pipe 240 c. The upstreamside of the liquid source supply pipe 240 c is placed in the liquidsource stored in the liquid source supply tank 266. An on-off valve 243c, a liquid mass flow controller (LMFC) 242 c, and an on-off valve 241 care installed at the liquid source supply pipe 240 c sequentially fromthe upstream side of the liquid source supply pipe 240 c. A downstreamside of a pressurizing gas supply pipe 240 d is connected to the topside of the liquid source supply tank 266 for supplying inert gas(pressurizing gas) such as N₂ gas. The upstream side of the pressurizinggas supply pipe 240 d is connected to a pressurizing gas supply source(not shown) that supplies inert gas such as He gas as a pressurizinggas. At the pressurizing gas supply pipe 240 d, an on-off valve 241 d isinstalled. By opening the on-off valve 241 d, a pressuring gas can besupplied to the inside of the liquid source supply tank 266, and byopening the on-off valves 243 c and 241 c, a liquid source can bepressure-fed (supplied) from the liquid source supply tank 266 to thevaporizer 260 for generating a vaporized gas inside the liquid sourcesupply tank 266. The flowrate of the liquid source supplied to thevaporizer 260 (that is, the flowrate of a vaporized gas generated in thevaporizer 260 and supplied to the inside of the inner tube 204) can becontrolled by using the LMFC 242 c.

A carrier gas supply source (not shown) is connected to the upstreamside of the carrier gas supply pipe 240 f for supplying inert gas(carrier gas) such as N₂ gas. A mass flow controller (MFC) 242 f and anon-off valve 241 f are sequentially installed from the upstream side ofthe carrier gas supply pipe 240 f. By opening the on-off valve 241 f andthe on-off valve 241 a, a carrier gas can be supplied to the vaporizer260, and a gas mixture of the carrier gas and vaporized gas generated inthe vaporizer 260 can be supplied to the inside of the inner tube 204through the vaporized gas supply pipe 240 a and the vaporized gas nozzle233 a. By supplying carrier gas to the inside of the vaporizer 260,discharge of vaporized gas from the vaporizer 260, and supply ofvaporized gas to the inside of the inner tube 204 can be facilitated.The flowrate of carrier gas supplied to the inside of the vaporizer 260(that is, the flowrate of carrier gas supplied to the inside of theinner tube 204) can be controlled by using the MFC 242 f.

A vaporized gas supply unit, which supplies vaporized gas (first sourcegas) to the inside of the inner tube 204 through the vaporized gasnozzle 233 a, is constituted mainly by the vaporized gas supply pipe 240a, the vaporizer 260, the on-off valve 241 a, the liquid source supplypipe 240 c, the on-off valve 243 c, the LMFC 242 c, the on-off valve 241c, the liquid source supply tank 266, the pressurizing gas supply pipe240 d, the pressurizing gas supply source (not shown), the on-off valve241 d, the carrier gas supply pipe 240 f, the carrier gas supply source(not shown), the MFC 242 f, and the on-off valve 241 f.

(Reaction Gas Supply Unit)

To a horizontal end (upstream side) of the reaction gas nozzle 233 bwhich protrudes from the sidewall of the manifold 209, a reaction gassupply pipe 240 b is connected. An ozonizer 270 is connected to anupstream side of the reaction gas supply pipe 240 b for generating ozone(O₃) gas (an oxidizer) as a second source gas. An MFC 242 b and anon-off valve 241 b are sequentially installed from the upstream side ofthe reaction gas supply pipe 240 b. The downstream side of an oxygen gassupply pipe 240 e is connected to the ozonizer 270. The upstream side ofthe oxygen gas supply pipe 240 e is connected to an oxygen gas supplysource (not shown) that supplies oxygen (O₂) gas. An on-off valve 241 eis installed at the oxygen gas supply pipe 240 e. By opening the on-offvalve 241 e, oxygen gas can be supplied to the ozonizer 270, and byopening the on-off valve 241 b, ozone gas generated in the ozonizer 270can be supplied to the inside of the inner tube 204 through the reactiongas supply pipe 240 b. The flowrate of ozone gas supplied to the insideof the inner tube 204 can be controlled by using the MFC 242 b.

Mainly by the reaction gas supply pipe 240 b, the ozonizer 270, the MFC242 b, the oxygen gas supply pipe 240 e, the oxygen gas supply source(not shown), and the on-off valve 241 e, a reaction gas supply unit isconstituted to supply ozone gas (second source gas) to the inside of theinner tube 204 through the reaction gas nozzle 233 b.

(Vent Pipe)

The upstream side of a vaporized gas vent pipe 240 i is connected to thevaporized gas supply pipe 240 a between the vaporizer 260 and the on-offvalve 241 a. The downstream side of the vaporized gas vent pipe 240 i isconnected to the downstream side of an exhaust pipe 231 (describedlater) between an automatic pressure control (APC) valve 231 a(described later) and a vacuum pump 231 b (described later). An on-offvalve 241 i is installed at the vaporized gas vent pipe 240 i. Byclosing the on-off valve 241 a and opening the on-off valve 241 i,supply of vaporized gas to the inside of the inner tube 204 can beinterrupted while continuing generation of vaporized gas inside thevaporizer 260. Since it takes a predetermined time to generate vaporizedgas stably, it is configured such that switching between supply andnon-supply of vaporized gas to the inside of the inner tube 204 can becarried out within a very short time by switching the on-off valve 241 aand the on-off valve 241 i.

Similarly, the upstream side of a reaction gas vent pipe 240 j isconnected to the reaction gas supply pipe 240 b between the ozonizer 270and the MFC 242 b. The downstream side of the reaction gas vent pipe 240j is connected to the downstream side of the exhaust pipe 231 (betweenthe APC valve 231 a (described later) and the vacuum pump 231 b(described later)). An on-off valve 241 j and an ozone eliminationdevice (not shown) are sequentially installed from the upstream side ofthe reaction gas vent pipe 240 j. By closing the on-off valve 241 b andopening the on-off valve 241 j, supply of ozone gas to the inside of theinner tube 204 can be interrupted while continuing generation of ozonegas inside the ozonizer 270. Since it takes a predetermined time togenerate ozone gas stably, it is configured such that switching betweensupply and non-supply of ozone gas to the inside of the inner tube 204can be carried out within a very short time by switching the on-offvalve 241 b and the on-off valve 241 j.

(Inert Gas Supply Pipe)

The downstream side of a first inert gas supply pipe 240 g is connectedto the downstream side of the on-off valve 241 a of the vaporized gassupply pipe 240 a. An inert gas supply source (not shown) configured tosupply inert gas such as N₂ gas, an MFC 242 g, and an on-off valve 241 gare sequentially installed from the upstream side of the first inert gassupply pipe 240 g. Similarly, the downstream side of a second inert gassupply pipe 240 h is connected to the downstream side of the on-offvalve 241 b of the reaction gas supply pipe 240 b. An inert gas supplysource (not shown) configured to supply inert gas such as N₂ gas, an MFC242 h, and an on-off valve 241 h are sequentially installed from theupstream side of the second inert gas supply pipe 240 h.

Inert gas supplied through the first inert gas supply pipe 240 g and thesecond inert gas supply pipe 240 h is used as a carrier gas or purgegas.

For example, by closing the on-off valve 241 i and opening the on-offvalve 241 a and the on-off valve 241 g, gas (a gas mixture of vaporizedgas and carrier gas) output from the vaporizer 260 can be supplied tothe inside of the inner tube 204 while diluting the gas output from thevaporizer 260 with inert gas (carrier gas) supplied from the first inertgas supply pipe 240 g. Similarly, by closing the on-off valve 241 j andopening the on-off valve 241 b and the on-off valve 241 h, reaction gasoutput from the ozonizer 270 can be supplied to the inside of the innertube 204 while diluting the reaction gas with inert gas (carrier gas)supplied from the second inert gas supply pipe 240 h.

In addition, gas dilution can be performed in the preliminary chamber201 a. That is, by closing the on-off valve 241 i and opening the on-offvalve 241 a and the on-off valve 241 h, gas (a gas mixture of vaporizedgas and carrier gas) output from the vaporizer 260 can be supplied tothe inside of the inner tube 204 while diluting the gas in thepreliminary chamber 201 a with inert gas (carrier gas) supplied from thesecond inert gas supply pipe 240 h. Similarly, by closing the on-offvalve 241 j and opening the on-off valve 241 b and the on-off valve 241g, ozone gas output from the ozonizer 270 can be supplied to the insideof the inner tube 204 while diluting the ozone gas in the preliminarychamber 201 a with inert gas (carrier gas) supplied from the first inertgas supply pipe 240 g.

In addition, while continuing generation of vaporized gas in thevaporizer 260, supply of vaporized gas to the inside of the inner tube204 can be interrupted by closing the on-off valve 241 a and opening theon-off valve 241 i, and at the same time, inert gas (purge gas) can besupplied from the first inert gas supply pipe 240 g and the second inertgas supply pipe 240 h to the inside of the inner tube 204 by opening theon-off valve 241 g and the on-off valve 241 h. Similarly, whilecontinuing generation of ozone gas in the ozonizer 270, supply of ozonegas to the inside of the inner tube 204 can be interrupted by closingthe on-off valve 241 b and opening the on-off valve 241 j, and at thesame time, inert gas (purge gas) can be supplied from the first inertgas supply pipe 240 g and the second inert gas supply pipe 240 h to theinside of the inner tube 204 by opening the on-off valve 241 g and theon-off valve 241 h. In the way, by supplying inert gas (purge gas) tothe inside of the inner tube 204, discharge of vaporized gas or ozonegas from the inside of the inner tube 204 can be facilitated.

(Gas Exhaust Part and Gas Exhaust Outlets)

At the sidewall of the inner tube 204, a gas exhaust part 204 b isformed along a stacked direction of wafers 200 as part of the sidewallof the inner tube 204. The gas exhaust part 204 b is formed at aposition facing the vaporized gas nozzle 233 a and the reaction gasnozzle 233 b with the wafers 200 being disposed therebetween (that is,at a position about 180-degree opposite to the vaporized gas nozzle 233a and the reaction gas nozzle 233 b). Furthermore, in thecircumferential direction of the inner tube 204, the width of the gasexhaust part 204 b is greater than the distance between the vaporizedgas nozzle 233 a and the reaction gas nozzle 233 b.

At the sidewall of the gas exhaust part 204 b, gas exhaust outlets 204 aare formed. The gas exhaust outlets 204 a are formed at positions facingthe vaporized gas nozzle 233 a and the reaction gas nozzle 233 b withthe wafers 200 being disposed therebetween (that is, at positions about180-degree opposite to the vaporized gas nozzle 233 a and the reactiongas nozzle 233 b). The gas exhaust outlets 204 a relevant to the currentembodiment have a hole shape and are formed at positions (heights)corresponding to the wafers 200, respectively. Therefore, a space 203 aformed between the outer tube 203 and the inner tube 204 communicateswith the inside of the inner tube 204 through the gas exhaust outlets204 a. The diameters of the gas exhaust outlets 204 a can be properlyadjusted to obtain adequate gas flowrate and velocity distributionsinside the inner tube 204. For example, the diameters of the gas exhaustoutlets 204 a may be adjusted to be uniform or gradually increased fromthe lower side to the upper side.

The shape of the gas exhaust outlets 204 a relevant to the presentinvention is not limited to the hole shape shown in FIG. 6, and thepositions of the gas exhaust outlets 204 a are not limited to positions(heights) corresponding to respective wafers 200. For example, as shownin FIG. 7, a slit may be formed along the stacked direction of wafers200 as a gas exhaust outlet 204 a. The width of the slit may be properlyadjusted to obtain adequate gas flowrate and velocity distributionsinside the inner tube 204. For example, the width of the slit may beadjusted to be uniform or gradually decreased from the lower side to theupper side.

In addition, as shown in the cross sectional view of the process tube205 of FIG. 5, the sidewall of the inner tube 204 relevant to thecurrent embodiment is configured such that the distance L2 between theouter edge of a wafer 200 accommodated in the inner tube 204 and the gasexhaust outlet 204 a is greater than the distance L1 between the outeredge of the wafer 200 accommodated in the inner tube 204 and thevaporized gas injection hole 248 a. Furthermore, the sidewall of theinner tube 204 relevant to the current embodiment is configured suchthat the distance L2 between the outer edge of the wafer 200accommodated in the inner tube 204 and the gas exhaust outlet 204 a isgreater than the distance L1 between the outer edge of the wafer 200accommodated in the inner tube 204 and the reaction gas injection hole248 b. Furthermore, in the circumferential direction of the inner tube204 relevant to the current embodiment, the width of the gas exhaustpart 204 b is greater than the distance between the vaporized gas nozzle233 a and the reaction gas nozzle 233 b. However, the present inventionis not limited to the above-described structures.

(Exhaust Unit)

The exhaust pipe 231 is connected to the sidewall of the manifold 209. Apressure sensor 245 used as a pressure detector, the APC valve 231 aused as a pressure regulator, the vacuum pump 231 b used as a vacuumexhaust device, and a toxicant removing machine 231 c configured toremove toxic substances from exhaust gas are sequentially installed fromthe upstream side of the exhaust pipe 231. By controlling the APC valve231 a while operating the vacuum pump 231 b, the inside pressure of theinner tube 204 can be adjusted to a desired level. An exhaust unit isconstituted mainly by the exhaust pipe 231, the pressure sensor 245, theAPC valve 231 a, the vacuum pump 231 b, and the toxicant removingmachine 231 c.

As described above, the space 203 a formed between the outer tube 203and the inner tube 204 communicates with the inside space of the innertube 204 through the gas exhaust outlets 204 a. Therefore, by exhaustingthe space 203 a formed between the outer tube 203 and the inner tube 204through the exhaust unit while supplying gas to the inside of the innertube 204 through the vaporized gas nozzle 233 a or the reaction gasnozzle 233 b, horizontal gas streams 10 can be produced inside the innertube 204 in a direction from the vaporized gas injection holes 248 a orthe reaction gas injection holes 248 b to the gas exhaust outlets 204 a.

(Controller)

The controller 280 used as a control unit is connected to devices suchas the heater 207, the APC valve 231 a, the vacuum pump 231 b, therotary mechanism 267, the boat elevator 115, the on-off valves 241 a,241 b, 241 c, 241 d, 241 e, 241 f, 241 g, 241 h, 241 i, and 241 j, theLMFC 242 c, and the MFCs 242 b, 242 f, 242 g, and 242 h. The controller280 controls the temperature adjustment operation of the heater 207; theopening/closing and pressure adjustment operations of the APC valve 231a; the operation of the vacuum pump 231 b; the rotation velocityadjustment operation of the rotary mechanism 267; the elevatingoperation of the boat elevator 115; the opening/closing operations ofthe on-off valves 241 a, 241 b, 241 c, 241 d, 241 e, 241 f, 241 g, 241h, 241 i, and 241 j; and the flowrate adjust operations of the LMFC 242c and the MFCs 242 b, 242 f, 242 g, and 242 h

The controller 280 controls the gas supply units and the exhaust unit tosupply at least two kinds of gases to the inside of the inner tube 204by turns while keeping the gases from mixing together. For this end,when gas is supplied to the inside of the inner tube 204, the controller280 the controls the gas supply units and the exhaust unit to keep theinside pressure of the inner tube 204 in the range from 10 Pa to 700 Pa.Specifically, when vaporized gas is supplied to the inside of the innertube 204, the controller 280 controls the vaporized gas supply unit andthe exhaust unit to keep the inside pressure of the inner tube 204, forexample, in the range from 10 Pa to 700 Pa (preferably, 250 Pa). Inaddition, when reaction gas is supplied to the inside of the inner tube204, the controller 280 controls the reaction gas supply unit and theexhaust unit to keep the inside pressure of the inner tube 204, forexample, in the range from 10 Pa to 300 Pa (preferably, 100 Pa).

(4) Substrate Processing Process

Next, as an embodiment of the present invention, a substrate processingprocess will be explained with reference to FIG. 9 and FIG. 11. In thecurrent embodiment, TEMAZr gas (vaporized gas) is used as a first sourcegas, and ozone gas (reaction gas) is used as a second source gas, so asto perform a method of forming a high-k (high dielectric constant) filmon a wafer 200, as one of semiconductor device manufacturing processes,by using an atomic layer deposition (ALD) method which is a kind ofchemical vapor deposition (CVD) method. In the following description,the controller 280 controls parts of the substrate processing apparatus101.

(Substrate Loading Operation S10)

First, a plurality of wafers 200 are charged into the boat 217. Next,the boat 217, in which the plurality of wafers 200 are horizontally heldin a stacked state, is lifted by the boat elevator 115 to load the boat217 into the inner tube 204 (boat loading). In this state, the loweropening (furnace port) of the manifold 209 is sealed by the seal cap 219with the O-ring 220 b being disposed between the seal cap 219 and themanifold 209. In the substrate loading operation S10, it is preferablethat purge gas is continuously supplied to the inside of the inner tube204 by opening the on-off valve 241 g and the on-off valve 241 h.

(Depressurizing and Temperature Increasing Operation S20)

Next, the on-off valve 241 g and the on-off valve 241 h are closed, andthe inside of the inner tube 204 is exhausted by using the vacuum pump231 b so as to adjust the pressure of the inside of the inner tube 204(the inside of the process chamber 201) to a desired process pressure(vacuum degree). At this time, the opened area of the APC valve 231 a isfeedback controlled based on temperature information measured by usingthe pressure sensor 245. In addition, to keep the surfaces of the wafers200 at a desired temperature (process temperature), power supply to theheater 207 is controlled. At this time, power supply to the heater 207is feedback controlled based on temperature information measured byusing a temperature sensor. Thereafter, the boat 217 and the wafers 200are rotated by using the rotary mechanism 267.

Exemplary conditions at the end of the depressurizing and temperatureincreasing operation S20 are follows.

Process pressure: 10 Pa to 1000 Pa, preferably 50 Pa

Process temperature: 180° C. to 250° C., preferably 220° C.

(Film Forming Operation S30)

Next, a cycle of a vaporized gas supply operation S31 to a purgeoperation S34 (described later) is repeated for a predetermined numberof times to form high-k films (ZrO₂ film) on the wafers 200 to a desiredthickness. FIG. 11 shows exemplary gas supply sequences of the vaporizedgas supply operation S31 to purge operation S34.

(Vaporized Gas Supply Operation S31)

First, the on-off valve 241 d is opened to supply pressurizing gas tothe inside of the liquid source supply tank 266. Next, the on-off valve243 c and the on-off valve 241 c are opened to press (supply) a liquidsource such as TEMAZr from the inside of the liquid source supply tank266 to the inside of the vaporizer 260 so as to generate TEMAZr gas(vaporized gas) by vaporizing the liquid TEMAZr. In addition, the on-offvalve 241 f is opened to supply N₂ gas (carrier gas) to the inside ofthe vaporizer 260. Until the TEMAZr gas is stably generated, the on-offvalve 241 a is closed, and the on-off valve 241 i is opened, so as todischarge a gas mixture of TEMAZr gas and N₂ gas through the vaporizedgas vent pipe 240 i.

After TEMAZr gas is stably generated, the on-off valve 241 i is closed,and the on-off valve 241 a is opened, so as to supply a gas mixture ofTEMAZr gas and N₂ gas to the inside of the inner tube 204 through thevaporized gas nozzle 233 a. At this time, the on-off valve 241 g isopened so as to supply the gas mixture from the vaporizer 260 to theinside of the inner tube 204 while diluting the gas mixture with N₂ gas(carrier gas) supplied through the first inert gas supply pipe 240 g. Atthis time, for example, the flowrate of TEMAZr gas may be 0.35 g/min;the flowrate of N₂ gas supplied through the carrier gas supply pipe 240f may be 1 slm; the flowrate of N₂ gas supplied through the first inertgas supply pipe 240 g may be 8 slm; and the flowrate of N₂ gas suppliedthrough the second inert gas supply pipe 240 h may be 2 slm.

Horizontal gas streams 10 are formed in a direction from the vaporizedgas injection holes 248 a to the gas exhaust outlets 204 a by the gasmixture supplied to the inside of the inner tube 204 through thevaporized gas nozzle 233 a, and the horizontal gas streams 10 aredischarged through the exhaust pipe 231. At this time, TEMAZr gas issupplied to the surfaces of the stacked wafers 200, and thus moleculesof the TEMAZr gas are adsorbed into the surfaces of the wafers 200.

After performing the process continuously for a predetermined time (forexample, 120 seconds), the on-off valve 241 a is closed, and the on-offvalve 241 i is opened, so as to interrupt supply of TEMAZr gas to theinside of the inner tube 204 while continuously generating the TEMAZrgas. In a state where the on-off valve 241 f is opened, supply of N₂ gasto the vaporizer 260 is continued.

(Purge Operation S32)

Next, the on-off valve 241 g and the on-off valve 241 h are opened tosupply N₂ (purge gas) to the inside of the inner tube 204. At this time,for example, the flowrate of N₂ gas supplied from the first inert gassupply pipe 240 g may be 5 slm, and the flowrate of N₂ gas supplied fromthe second inert gas supply pipe 240 h may be 4 slm. Owing to this,discharge of TEMAZr gas from the inside of the inner tube 204 isfacilitated. If the inside atmosphere of the inner tube 204 is replacedwith N₂ gas after a predetermined time (for example, 20 seconds), theon-off valve 241 g and the on-off valve 241 h are closed to interruptsupply of N₂ gas to the inside of the inner tube 204. Then, the insideof the inner tube 204 is exhausted for a predetermined time (forexample, 20 seconds).

(Reaction Gas Supply Operation S33)

Next, the on-off valve 241 e is opened to supply oxygen gas to theozonizer 270 so as to generate ozone gas (an oxidizer) as a reactiongas. Until ozone gas is stably generated, the on-off valve 241 b isclosed, and the on-off valve 241 j is opened, in order to dischargeozone gas through the reaction gas vent pipe 240 j.

After ozone gas is stably generated, the on-off valve 241 j is closed,and the on-off valve 241 b is opened, to supply ozone gas to the insideof the inner tube 204 through the reaction gas nozzle 233 b. At thistime, the on-off valve 241 g is opened so that the ozone gas can besupplied to the inside of the inner tube 204 through the reaction gasnozzle 233 b while being diluted at the preliminary chamber 201 a withN₂ gas (carrier gas) supplied through the first inert gas supply pipe240 g. At this time, for example, the flowrate of ozone gas may be 6slm, and the flowrate of N₂ gas supplied through the first inert gassupply pipe 240 g may be 2 slm.

By ozone gas supplied to the inside of the inner tube 204 through thereaction gas nozzle 233 b, horizontal gas streams 10 are formed in adirection from the reaction gas injection holes 248 b to the gas exhaustoutlets 204 a, and the horizontal gas streams 10 are discharged throughthe exhaust pipe 231. In this way, ozone gas is supplied to the surfacesof the stacked wafers 200 and chemically reacts with molecules of TEMAZrgas adsorbed in the surfaces of the wafers 200, so that high-k films(ZrO₂ film) each constituted by one to several atomic layers can beformed on the wafers 200.

After reaction gas is supplied for a predetermined time, the on-offvalve 241 b is closed, and the on-off valve 241 j is opened, so as tointerrupt supply of reaction gas to the inside of the inner tube 204while continuing generation of ozone gas.

(Purge Operation S34)

Next, the on-off valve 241 g and the on-off valve 241 h are opened tosupply N₂ gas (purge gas) to the inside of the inner tube 204. At thistime, for example, the flowrate of N₂ gas supplied through the firstinert gas supply pipe 240 g may be 4 slm, and the flowrate of N₂ gassupplied through the second inert gas supply pipe 240 h may be 4 slm.Therefore, discharge of ozone gas and reaction gas from the inside ofthe inner tube 204 is facilitated. If the inside atmosphere of the innertube 204 is replaced with N₂ gas after a predetermined time (forexample, 10 seconds), the on-off valve 241 g and the on-off valve 241 hare closed to interrupt supply of N₂ gas to the inside of the inner tube204. Thereafter, the inside of the inner tube 204 is exhausted for apredetermined time (for example, 15 seconds).

Then, the vaporized gas supply operation S31 to the purge operation S34are bounded as a cycle, and the cycle is repeated for a predeterminednumber of times, to supply TEMAZr gas and ozone gas to the inside of theinner tube 204 by turns without mixing, so as to form high-k films(ZrO₂) on the wafers 200 to a desired thickness (film forming operationS30). The process conditions of the above-described processes are notlimited to the above-mentioned values or ranges. For example, theprocess conditions shown in FIG. 13 can be used.

<Conditions of Vaporized Gas Supply Operation S31>

Process pressure: 10 Pa to 700 Pa, preferably 250 Pa

TEMAZr gas flowrate: 0.01 g/min to 0.35 g/min, preferably 0.3 g/min

N₂ gas flowrate: 0.1 slm to 1.5 slm, preferably 1.0 slm

Process temperature: 180° C. to 250° C., preferably 220° C.

Process time: 30 seconds to 180 seconds, preferably 120 seconds

<Conditions of Purge Operation S32>

Process pressure: 10 Pa to 100 Pa, preferably 70 Pa

N₂ gas flowrate: 0.5 slm to 20 slm, preferably 12 slm

Process temperature: 180° C. to 250° C., preferably 220° C.

Process time: 30 seconds to 150 seconds, preferably 60 seconds

<Conditions of Reaction Gas Supply Operation S33>

Process pressure: 10 Pa to 300 Pa, preferably 100 Pa

Ozone gas flowrate: 6 slm to 20 slm, preferably 17 slm

N₂ gas flowrate: 0 slm to 2 slm, preferably 0.5 slm

Process temperature: 180° C. to 250° C., preferably 220° C.

Process time: 10 seconds to 300 seconds, preferably 120 seconds

<Conditions of Purge Operation S34>

Process pressure: 10 Pa to 100 Pa, preferably 70 Pa

N₂ gas flowrate: 0.5 slm to 20 slm, preferably 12 slm

Process temperature: 180° C. to 250° C., preferably 220° C.

Process time: 10 seconds to 90 seconds, preferably 60 seconds

(Atmospheric Pressure Return Operation S40, Substrate UnloadingOperation S50)

After the high-k films (ZrO₂) having a desired thickness are formed onthe wafers 200, the opened area of the APC valve 231 a is reduced, andthe on-off valve 241 g and the on-off valve 241 h are opened to supplypurge gas to the inside of the inner tube 204 until the inside pressureof the process tube 205 (the inside pressures of the inner tube 204 andthe outer tube 203) becomes atmospheric pressure (S40). Thereafter, thewafers 200 on which films are formed are unloaded from the inside of theinner tube 204 in the reverse order to that of the substrate loadingoperation S10 (S50). In the substrate unloading operation S50, it ispreferable that the on-off valve 241 g and the on-off valve 241 h beopened for continuing supply of purge gas.

(5) Effects Relevant to the Current Embodiment

According to the current embodiment, one or more effects can be attainedas follows.

(a) According to the current embodiment, in the boat 217, a region lowerthan a region where wafers 200 are stacked is surrounded by the gaspenetration preventing cylinder 217 f having a cylindrical shape.Therefore, gas supplied to inside of the inner tube 204 is allowed toflow in the region of the boat 217 where the wafers 200 are stacked butis restrained from flowing in a region lower than the region. That is,supply of TEMAZr gas or ozone gas can be facilitated between wafers 200held at lower positions than the other wafers 200 held in the boat 217,and thus it can be prevented that the velocity of supplied TEMAZr gas orozone gas is lowered at the center parts of the lower wafers 200,thereby improving the uniformity of substrate processing quality in thesurfaces of the wafers 200 and between the wafers 200.

For reference, the structure of a process furnace 202′ of a conventionalsubstrate processing apparatus is illustrated in FIG. 17. Referring toFIG. 17, in a boat 217′ of the conventional substrate processingapparatus, a plurality of disk-shaped insulation plates 217 g′ made of amaterial such as quartz or silicon carbide are horizontally oriented andstacked in a region lower than stacked wafers 200. That is, in the boat217′ of the conventional substrate processing apparatus, a gaspenetration preventing cylinder 217 f is not installed in the regionlower than the stacked wafers 200. Therefore, gas supplied to the insideof an inner tube 204′ may not flow between the wafers 200 but flow inthe region of the boat 217′ lower than the wafers 200, so that thevelocity of gas supplied to lower wafers 200 can be lowered (the amountof supplied gas can be reduced) to degrade the uniformity of substrateprocessing quality in the surfaces of the wafers 200 and between thewafers 200.

(b) According to the current embodiment, in a state where the boat 217is accommodated in the inner tube 204, the distance between the upperend plate 217 c of the boat 217 and the top plate of the inner tube 204is smaller than the distance (stack pitch) between stacked wafers 200.That is, the conductance of the space between the upper end plate 217 cand the top plate of the inner tube 204 is smaller than the conductanceof a region where the wafers 200 are stacked, and a gas flow is noteasily created at the space between the upper end plate 217 c and thetop plate of the inner tube 204. Therefore, TEMAZr gas or ozone gassupplied to the inside of the inner tube 204 can be restrained fromflowing between the upper end plate 217 c and the top plate of the innertube 204 instead of flowing between the wafers 200, and thus supply ofTEMAZr gas or ozone gas to gaps between wafers 200 held at highpositions can be facilitated. Therefore, it can be prevented that thevelocity of supplied TEMAZr gas or ozone gas is lowered at the centerparts of the highly-positioned wafers 200, and thus the uniformity ofsubstrate processing quality can be improved in the surfaces of thewafer 200 and between the wafers 200.

However, in the case of the conventional substrate processing apparatus,as shown in FIG. 17, the distance between an upper end plate 217 c′ ofthe boat 217′ and the top plate of the inner tube 204′ is greater thanthe distance (stack pitch) between the stacked wafers 200. That is, theconductance of the space between the upper end plate 217 c′ and the topplate of the inner tube 204′ is greater than the conductance of a regionwhere the wafers 200 are stacked. Therefore, instead of flowing betweenthe wafers 200, gas supplied to the inside of the inner tube 204′ canflow between the upper end plate 217 c′ and the top plate of the innertube 204′, and thus the velocity of gas supplied to upper wafers 200 canbe lowered (the amount of supplied gas can be reduced) to degrade theuniformity of substrate processing quality in the surfaces of the wafers200 and between the wafers 200.

(c) According to the current embodiment, in a state where the boat 217is accommodated in the inner tube 204, the distance between the innerwall of the inner tube 204 and the gas penetration preventing cylinder217 f is shorter than the distance between stacked wafers 200. That is,the conductance of the space between the inner wall of the inner tube204 and the gas penetration preventing cylinder 217 f is smaller thanthe conductance of a region where the wafers 200 are stacked, and thus agas flow is not easily created at the space between the inner wall ofthe inner tube 204 and the gas penetration preventing cylinder 217 f.Therefore, TEMAZr gas or ozone gas supplied to the inside of the innertube 204 can be restrained from flowing between the inner wall of theinner tube 204 and the gas penetration preventing cylinder 217 f insteadof flowing between the wafers 200, and thus supply of TEMAZr gas orozone gas to gaps between wafers 200 held at lower positions can befacilitated. Therefore, it can be prevented that the velocity ofsupplied TEMAZr gas or ozone gas is lowered at the center parts of thelower-positioned wafers 200, and thus the uniformity of substrateprocessing quality can be improved in the surfaces of the wafers 200 andbetween the wafers 200.

However, in the case of the conventional substrate processing apparatus,as shown in FIG. 17, the distance between the inner wall of the innertube 204′ and the outer peripheries of the insulation plates 217 g′ heldin the boat 217′ is greater than the distance (stack pitch) between thestacked wafers 200. That is, the conductance of the space between theinner wall of the inner tube 204′ and the outer peripheries of theinsulation plates 217 g′ is greater than the conductance of a regionwhere the wafers 200 are stacked. Therefore, instead of flowing betweenthe wafers 200, gas supplied to the inside of the inner tube 204′ canflow between the inner wall of the inner tube 204′ and the outerperipheries of the insulation plates 217 g′, and thus the velocity ofgas supplied to lower wafers 200 can be lowered (the amount of suppliedgas can be reduced) to degrade the uniformity of substrate processingquality in the surfaces of the wafers 200 and between the wafers 200.

The effects explained in sections (a) to (c) are shown in FIG. 15. InFIG. 15, the horizontal axis denotes the position of wafers held in aboat—the left side of the horizontal axis denotes the lower inner sideof the boat, and the right side of the horizontal axis denotes the upperinner side of the boat. The vertical axis denotes the velocity of gasmeasured at the centers of the surfaces of the wafers 200. The curve (a)indicated by ▪ denotes measured values (Example) in the case of asubstrate processing apparatus relevant to the current embodiment, andthe curve (b) indicated by ⋄ denotes measured values (ComparisonExample) in the case of a conventional substrate processing apparatus.Referring to FIG. 15, it will be understood that the velocity of gassupplied to the center parts of the surfaces of wafers 200 held at upperor lower positions is less reduced in the case (curve (a)) of thesubstrate processing apparatus relevant to the current embodiment ascompared with the case (curve (b)) of the conventional substrateprocessing apparatus. In addition, it will be understood that substrateprocessing efficiency can be increased because the velocity of gas canbe entirely increased.

(d) According to the current embodiment, the top and bottom openings ofthe gas penetration preventing cylinder 217 f are air-tightly closed bythe cover plate 217 e and the end plate 217 d, respectively. Therefore,TEMAZr gas or ozone gas can be restrained from penetrating into the gaspenetration preventing cylinder 217 f and collecting in the gaspenetration preventing cylinder 217 f, and thus generation of particlesthat lowers substrate processing quality can be suppressed. However, inthe case of the conventional substrate processing apparatus illustratedin FIG. 17, TEMAZr gas ozone gas can easily flow to a region of the boat217′ (where the insulation plates 217 g′ are stacked) lower than aregion where the wafers 200 are stacked, and thus particles can beeasily generated due to TEMAZr gas or ozone gas collected in the lowerregion of the boat 217′.

(e) According to the current embodiment, at the lower side of thesidewall of the gas penetration preventing cylinder 217 f, at least onevent hole 217 g is formed. In this way, by forming the vent hole 217 gat the sidewall of the gas penetration preventing cylinder 217 f, theinside of the inner tube 204 can be exhausted (pressure-adjusted)rapidly and stably. In addition, since the vent hole 217 g is formed notat the upper side but at the lower side of the sidewall of the gaspenetration preventing cylinder 217 f, TEMAZr gas or ozone gas can berestrained from penetrating into the gas penetration preventing cylinder217 f, thereby suppressing generation of particles which are caused bysource gas collected in the gas penetration preventing cylinder 217 fand result in degradation of substrate processing quality.

As shown in FIG. 3, in the case where the top and bottom openings of thegas penetration preventing cylinder 217 f are air-tightly closed by thecover plate 217 e and the end plate 217 d, respectively, and the insideof the gas penetration preventing cylinder 217 f is previously evacuated(in the case where the gas penetration preventing cylinder 217 f isconfigured as a vacuum cap shape), since gas flows are not generatedtoward and from the gas penetration preventing cylinder 217 f, theinside of the inner tube 204 can be exhausted (pressure-adjusted) morerapidly and stably. By preventing gas from collecting in the gaspenetration preventing cylinder 217 f, generation of particles can alsobe suppressed.

(f) As shown in FIG. 5, the sidewall of the inner tube 204 relevant tothe current embodiment is configured such that the sidewall of the innertube 204 relevant to the current embodiment is configured such that thedistance L2 between the outer edge of a wafer 200 accommodated in theinner tube 204 and the gas exhaust outlet 204 a is greater than thedistance L1 between the outer edge of the wafer 200 accommodated in theinner tube 204 and the vaporized gas injection hole 248 a. Furthermore,the distance L2 between the outer edge of the wafer 200 accommodated inthe inner tube 204 and the gas exhaust outlet 204 a is greater than thedistance L1 between the outer edge of the wafer 200 accommodated in theinner tube 204 and the reaction gas injection hole 248 b. In this way,since the distance between the outer edge of the wafer and the gasexhaust outlets 204 a is sufficiently long, a region where the velocityof a gas stream 10 increases can be relatively distant from the wafer200 so that the velocity of the horizontal gas stream 10 can be uniformalong the wafer 200. Therefore, the flowrate of gas supplied to thewafer 200 can be uniformly maintained, and thus film thicknessuniformity can be improved.

Second Embodiment of the Present Invention

Hereinafter, a second embodiment of the present invention will bedescribed with reference to the attached drawings.

FIG. 4 is a vertical sectional view illustrating a process furnaceprovided in a substrate processing apparatus relevant to the secondembodiment of the present invention. FIG. 10 is a flowchart forexplaining a substrate processing process relevant to the secondembodiment of the present invention. FIG. 12 is a gas supply sequencediagram of a cleaning process relevant to the second embodiment of thepresent invention. FIG. 14 is a table showing exemplary processconditions of a cleaning process relevant to the second embodiment ofthe present invention.

(1) Structure of Substrate Processing Apparatus

The substrate processing apparatus relevant to the current embodiment isdifferent from the substrate processing apparatus described in theprevious embodiment in that a barrier gas supply unit is furtherprovided to supply inert gas to a space between the inner wall of aninner tube 204 and a gas penetration preventing cylinder 217 f in astate where a boat 217 is accommodated in the inner tube 204. Inaddition, the substrate processing apparatus relevant to the currentembodiment is different from the substrate processing apparatusdescribed in the previous embodiment in that a cleaning gas supply unitis further provided to supply cleaning gas to the inside of the innertube 204 through a vaporized gas nozzle 233 a and a reaction gas nozzle233 b. Other configurations are the same as those of the firstembodiment.

(Barrier Gas Supply Unit)

For example, the barrier gas supply unit includes a barrier gas supplypipe 240 k configured to supply inert gas such as N₂ gas to the insideof the inner tube 204 from a gap between a seal cap 219 and a rotationshaft 255. A barrier gas supply source (not shown) configured to supplyinert gas such as N₂ gas, an MFC 242 k, and an on-off valve 241 k aresequentially installed from the upstream side of the barrier gas supplypipe 240 k.

By opening the on-off valve 241 k in a state where the boat 217 isaccommodated in the inner tube 204, inert gas is supplied from the lowerinner side to the upper inner side of the inner tube 204, and the inertgas is filled in the space between the sidewall of the inner tube 204and the gas penetration preventing cylinder 217 f. Therefore, TEMAZr gasor ozone gas can be restrained from penetrating into the space betweenthe sidewall of the inner tube 204 and the gas penetration preventingcylinder 217 f, and thus formation of a film can be suppressed on thelower side of the inner wall of the inner tube 204 or the sidewall ofthe gas penetration preventing cylinder 217 f.

(Cleaning Gas Supply Unit)

The cleaning gas supply unit includes a first cleaning gas pipe 240 mconfigured to supply first cleaning gas such as boron trichloride (BCl₃)gas, and a second cleaning gas pipe 240 n configured to supply secondcleaning gas such as oxygen (O₂) gas. The downstream side of the firstcleaning gas pipe 240 m is connected to a vaporized gas supply pipe 240a at the downstream side of an on-off valve 241 a. The downstream sideof the second cleaning gas pipe 240 n is connected to a reaction gassupply pipe 240 b at the downstream side of an on-off valve 241 b. Afirst cleaning gas supply source (not shown) configured to supply BCl₃gas, an MFC 242 m, and an on-off valve 241 m are sequentially installedfrom the upstream side of the first cleaning gas pipe 240 m. A secondcleaning gas supply source (not shown) configured to supply O₂ gas, anMFC 242 n, and an on-off valve 241 n are sequentially installed from theupstream side of the second cleaning gas pipe 240 n.

By closing the on-off valve 241 a and opening the on-off valve 241 m,BCl₃ gas can be supplied to the inside of the inner tube 204 through thevaporized gas nozzle 233 a. In addition, by closing the on-off valve 241b and opening the on-off valve 241 n, O₂ gas can be supplied to theinside of the inner tube 204 through the reaction gas nozzle 233 b. Itis configured to such that BCl₃ gas and O₂ gas can be simultaneouslysupplied to the inside of the inner tube 204.

(2) Substrate Processing Process

A substrate processing process relevant to the current embodiment isdifferent from the substrate processing process described in theprevious embodiment in that inert gas is supplied to the space betweenthe inner tube 204 and the gas penetration preventing cylinder 217 f ina film forming operation S30. In addition, the substrate processingprocess relevant to the current embodiment is different from thesubstrate processing process described in the previous embodiment inthat a cleaning operation S80 is performed to remove depositedsubstances such as thin films from the inner wall of the inner tube 204or the like after performing the film forming operation S30 to asubstrate unloading operation S50.

(Substrate Loading Operation S10 to Substrate Unloading Operation S50)

Like in the previous embodiment, the substrate loading operation S10 tothe substrate unloading operation S50 are performed. In the currentembodiment, when a cycle of a vaporized gas supply operation S31 to apurge operation S34 is repeated for a predetermined number of times, theon-off valve 241 k is opened to supply N₂ gas (inert gas) to the insideof the inner tube 204 from the lower side to the upper side.

(Boat Loading Operation S60)

Next, the boat 217 in which wafers 200 are not charged is lifted byusing the boat elevator 115 to load the boat 217 into the inner tube 204(boat loading). In this state, the bottom side of a manifold 209 issealed by the seal cap 219 with an O-ring 220 b being disposedtherebetween. In the boat loading operation S60, it is preferable thaton-off valves 241 g and 241 h be opened for continuously supplying purgegas to the inside of the inner tube 204.

(Depressurizing and Temperature Increasing Operation S70)

Next, the on-off valve 241 g and the on-off valve 241 h are closed, andthe inside of the inner tube 204 (the inside of a process chamber 201)is exhausted by using a vacuum pump 231 b to a desired process pressure(vacuum degree). At this time, the opened area of an APC valve 231 a isfeedback controlled based on temperature information measured by using apressure sensor 245. In addition, to keep the inside of the inner tube204 at a desired temperature (process temperature), power supply to aheater 207 is controlled. At this time, power supply to the heater 207is feedback controlled based on temperature information measured througha temperature sensor. Thereafter, the boat 217 is rotated by using arotary mechanism 267.

Exemplary conditions at the end of the depressurizing and temperatureincreasing operation S70 are follows.

Process pressure: 1330 pa to 26600 Pa, preferably 1330 Pa

Process temperature: 300° C. to 700° C., preferably 540° C.

(Cleaning Operation S80)

Next, a cycle of a cleaning gas supply operation S81 to an exhaustoperation S83 (described later) is repeated for a predetermined numberof times so as to remove thin films formed on the inner wall of theinner tube 204 or the sidewall of the gas penetration preventingcylinder 217 f. FIG. 12 shows exemplary gas supply sequences of thecleaning gas supply operation S81 to the exhaust operation S83.

(Cleaning Gas Supply Operation S81)

First, the on-off valves 241 m and 241 n are opened in a state where theon-off valve 241 a and the on-off valves 241 g, 241 b, and 241 h areclosed, so that the inside of the inner tube 204 in which the boat 217is loaded can be simultaneously supplied with BCl₃ gas (first cleaninggas) through the vaporized gas nozzle 233 a and O₂ gas (second cleaninggas) through the reaction gas nozzle 233 b. In addition, the on-offvalve 241 k is opened to supply N₂ gas (inert gas) to the inside of theinner tube 204 in a direction from the lower side to the upper side. Atthis time, for example, the flowrate of BCl₃ gas supplied through thefirst cleaning gas pipe 240 m may be 1 slm; the flowrate of O₂ gassupplied through the second cleaning gas pipe 240 n may be 0.02 slm; andthe flowrate of N₂ gas supplied through the barrier gas supply pipe 240k may be 0.25 slm.

If the inside pressure of the inner tube 204 reaches a predeterminedprocess pressure (for example, 100 Torr) after a predetermined time (forexample, 270 seconds), the on-off valves 241 m, 241 n, and 241 k areclosed to interrupt supplies of BCl₃ gas, O₂ gas, and N₂ gas to theinside of the inner tube 204.

In addition, for example, the APC valve 231 a is closed forsubstantially stopping exhaustion of the inside of the process chamber201 (the inside of the inner tube 204) through an exhaust line.

(Sealing Operation S82)

Next, in a state where the exhaustion of the inside of the process tube205 (the inside of the inner tube 204) is substantially stopped, theinner tube 204 in which BCl₃ gas (first cleaning gas) and O₂ gas (secondcleaning gas) remain at a predetermined pressure (100 Torr) is sealedfor a predetermined time (for example, 180 seconds). As a result, thinfilms formed on places such as the inner wall of the inner tube 204 orthe sidewall of the gas penetration preventing cylinder 217 f areetched, and thus gas such as Zr chloride or Hf chloride is generated.

(Exhaust Operation S83)

Next, cleaning gas is exhausted from the inside of the inner tube 204.That is, in a state where the on-off valves 241 a, 241 g, 241 b, 241 h,241 m, 241 n, and 241 k are closed, the APC valve 231 a is opened toexhaust gas (such as cleaning gas, Zr chloride gas, or Hf chloride gas)remaining in the process tube 205. At this time, the on-off valves 241 gand 241 h can be opened to supply inert gas (purge gas) to the inside ofthe inner tube 204 so as to facilitate discharge of remaining gas fromthe inner tube 204.

Thereafter, a cycle of the cleaning gas supply operation S81 to theexhaust operation S83 is repeated for a predetermined number of times soas to etch thin films formed on the inner wall of the inner tube 204 orthe sidewall of the gas penetration preventing cylinder 217 f (S80). Theprocess conditions of the cleaning gas supply operation S81 are notlimited to the above-mentioned values or ranges. For example, theprocess conditions shown in FIG. 14 can be used.

<Process Conditions of Cleaning Gas Supply Operation S81>

Process pressure: 1330 Pa to 26600 Pa, preferably 13300 Pa

BCl₃ gas flowrate: 0.001 slm to 5 slm, preferably 1 slm

O₂ gas flowrate: 0 to 0.05 slm, preferably 1.0 slm

N₂ gas flowrate: 0.1 slm to 1 slm, preferably 0.15 slm

Process temperature: 300° C. to 700° C., preferably 540° C.

Thereafter, the opened area of the APC valve 231 a is reduced, and theon-off valves 241 g and 241 h are opened to supply purge gas to theinside of the inner tube 204 until the inside pressure of the processtube 205 (the inside pressures of the inner tube 204 and the outer tube203) becomes atmospheric pressure (S90).

(3) Effects Relevant to the Current Embodiment

According to the current embodiment, one or more effects can be attainedas follows.

(a) According to the current embodiment, when a cycle of the vaporizedgas supply operation S31 to the purge operation S34 is repeated for apredetermined number of times, the on-off valve 241 k is opened tosupply N₂ gas (inert gas) to the inside of the inner tube 204 from thelower side to the upper side. As a result, N₂ gas is filled in the spacebetween the inner wall of the inner tube 204 and the gas penetrationpreventing cylinder 217 f, which suppresses penetration of TEMAZr gas orozone gas into the space between the inner wall of the inner tube 204and the gas penetration preventing cylinder 217 f, and thus formation offilms on the lower side of the inner wall of the inner tube 204 or thesidewall of the gas penetration preventing cylinder 217 f can besuppressed.

(b) According to the current embodiment, since formation of thin filmson the lower side of the inner wall of the inner tube 204 or thesidewall of the gas penetration preventing cylinder 217 f can besuppressed, although thin films are formed on the lower side of theinner wall of the inner tube 204 or the sidewall of the gas penetrationpreventing cylinder 217 f, the thin films can be etched more rapidly andcompletely by performing the cleaning operation S80.

As described above, in the conventional substrate processing apparatusshown in FIG. 17, gas supplied to the inside of the inner tube 204′ mayflow in a space between the lower side of the inner wall of the innertube 204′ and the outer peripheries of the insulation plates 217 g′instead of flowing between wafers 200. Therefore, somewhat thick filmscan be formed on the lower side of the inner wall of the inner tube 204′or the insulation plates 217 g′. Furthermore, when the boat 217′ isaccommodated in the inner tube 204′, the lower part of the inner tube204′ or the insulation plates 217 g′ are located lower than a regionheated by the heater 207′. Therefore, although a cleaning process isperformed to supply cleaning gas to the inside of the inner tube 204′,since the temperature of the lower part of the inner tube 204′ or theinsulation plates 217 g′ is not sufficiently increased, etching rate maybe low, and etching residues (thin films which are not removed) mayexist on the lower side of the inner wall of the inner tube 204′ or theinsulation plates 217 g′. FIG. 16A is a schematic view illustratingpositions of etching residues remaining in a conventional substrateprocessing apparatus, and FIG. 16B is a graph showing a temperaturedistribution at the positions of etching residues. Referring to FIG.16A, etching residues can be observed at the lower side of the innerwall of the inner tube 204′ or the insulation plates 217 g′ (regional inFIG. 16A). In addition, referring to FIG. 16B, it can be understood thattemperature gradually decreases as it goes downward in the regionalwhere etching residues are exist, and this means that the etching ratedecreases as it goes downward.

In the substrate processing apparatus relevant to the currentembodiment, when the boat 217 is accommodated in the inner tube 204, atleast a part of the gas penetration preventing cylinder 217 f is alsolocated lower than a region heated by the heater 207. Therefore, whenthe cleaning operation S80 is performed, the temperature of the lateralsurface of the gas penetration preventing cylinder 217 f, or thetemperature of the lower side of the inner wall of the inner tube 204facing the gas penetration preventing cylinder 217 f is lower than thetemperature of a region where wafers 200 are stacked. However, in thecurrent embodiment, since formation of films can be suppressed at placessuch as the inner wall of the inner tube 204 or the sidewall of the gaspenetration preventing cylinder 217 f, although the gas penetrationpreventing cylinder 217 f is located lower than the region heated by theheater 207 (that is, although the etching rate is decreases), theabove-described problems can be solved.

Other Embodiments of the Present Invention

In the above-described embodiments, a material such as TEMAZr is used asa liquid source; however, the present invention is not limited thereto.That is, tetrakis(ethylmethylamino)hafnium (TEMAH) may be used as aliquid source, or an organic compound or chloride including one ofsilicon (Si), hafnium (Hf), zirconium (Zr), aluminum (Al), titanium(Ti), tantalum (Ta), ruthenium (Ru), iridium (Ir), germanium (Ge),antimony (Sb), and tellurium (Te) may be used as a liquid source.Furthermore, although TEMAZr gas obtained by vaporizing TEMAZr is usedas a first source gas in the above-described embodiments, the presentinvention is not limited thereto. For example, TEMAH gas obtained byvaporizing TEMAH may be used as a first source gas, or gas obtained byvaporizing or decomposing an organic compound or chloride including oneof silicon (Si), hafnium (Hf), zirconium (Zr), aluminum (Al), titanium(Ti), tantalum (Ta), ruthenium (Ru), iridium (Ir), germanium (Ge),antimony (Sb), and tellurium (Te) may be used as a first source gas.

In the above-described embodiments, ozone gas (oxidizer) is used as areaction gas. However, other oxidizers can be used. In addition, anitriding agent such as ammonia may be used as a reaction gas.

In the above-described embodiments, explanations are given on the casewhere a ZrO₂ film is formed on a wafer 200. However, the presentinvention can also be optimally applied to the case where one of ahafnium (Hf) oxide film, a silicon (Si) oxide film, an aluminum (Al)oxide film, a titanium (Ti) oxide film, a tantalum (Ta) oxide film, aruthenium (Ru) oxide film, an iridium (Ir) oxide film, a silicon (Si)nitride film, an aluminum (Al) nitride film, a titanium (Ti) nitridefilm, and a GeSbTe film is formed.

In the above-described embodiments, explanations are given on the caseof using an ALD method in which vaporized gas used as a first source gasand reaction gas used as a second source gas are alternately supplied toa wafer 200. However, the present invention is not limited thereto. Forexample, the present invention can be optimally applied to the case ofusing other methods such as a CVD method in which first and secondsource gases are simultaneously supplied to a wafer 200. In addition,the present invention is not limited to the case where two kinds ofgases are supplied to a wafer 200. For example, the present inventioncan be optimally applied to the case where a kind of gas is supplied orthree or more kinds of gases are supplied.

As described above, according to the substrate processing apparatus andthe semiconductor device manufacturing method relevant to the presentinvention, it can be prevented that the velocity of source gas decreasesat the center surface parts of substrates held at upper or lowerpositions of the substrate holder in which a plurality of substrates areheld, and thus, the uniformity of substrate processing quality can beimproved in the surfaces of the substrates and between the substrates.

Preferred Embodiments of the Present Invention

The present invention also includes the following embodiments.

(Supplementary Note 1)

According to a preferred embodiment of the present invention, there isprovided a substrate processing apparatus including: a substrate holderconfigured to hold a plurality of substrates in a state where thesubstrate are horizontally oriented and stacked; an inner tubeconfigured to accommodate the substrate holder; an outer tube configuredto enclose the inner tube; a gas nozzle installed in the inner tube; agas injection hole formed in the gas nozzle; a source gas supply unitconfigured to supply a source gas to an inside of the inner tube throughthe gas nozzle; a gas exhaust outlet formed in a sidewall of the innertube; an exhaust unit configured to exhaust a gap between the outer tubeand the inner tube so as to create a gas stream inside the inner tube ina direction from the gas injection hole to the gas exhaust outlet; and agas penetration preventing cylinder configured to enclose a region ofthe substrate holder lower than a region of the substrate holder wherethe substrates are stacked.

(Supplementary Note 2)

Preferably, the substrate processing apparatus further may include aheating unit installed around an outer periphery of the outer tube, andin a state where the substrate holder is accommodated in the inner tube,at least a part of the gas penetration preventing cylinder may belocated lower than a region heated by the heating unit.

(Supplementary Note 3)

Preferably, upper and lower ends of the gas penetration preventingcylinder may be air-tightly sealed, and at least one vent hole may beformed in a lower side of a sidewall of the gas penetration preventingcylinder.

(Supplementary Note 4)

Preferably, upper and lower ends of the gas penetration preventingcylinder may be air-tightly sealed, and an inside of the gas penetrationpreventing cylinder may be vacuum-exhausted.

(Supplementary Note 5)

Preferably, the gas penetration preventing cylinder may include acylinder made of quartz or silicon carbide.

(Supplementary Note 6)

Preferably, the substrate holder may include an upper end plate, and anupper end of the inner tube may be closed by a top plate, wherein in astate where the substrate holder is accommodated in the inner tube, adistance between the upper end plate of the substrate holder and the topplate of the inner tube may be shorter than a distance between thestacked substrates.

(Supplementary Note 7)

Preferably, a distance between an inner wall of the inner tube and thegas penetration preventing cylinder may be shorter than a distancebetween a distance between the stacked substrates.

(Supplementary Note 8)

Preferably, the substrate processing apparatus may further include abarrier gas supply unit configured to supply an inert gas to a spacebetween an inner wall of the inner tube and the gas penetrationpreventing cylinder in a state where the substrate holder isaccommodated in the inner tube.

(Supplementary Note 9)

Preferably, the substrate processing apparatus may further include: acover body configured to seal a lower opening of the outer tubeair-tightly; a rotation shaft disposed through the cover body forsupporting the substrate holder from a lower side of the substrateholder; and a rotary unit configured to rotate the rotation shaft,wherein the barrier gas supply unit supplies an inert gas to a gapbetween the cover body and the rotation shaft.

(Supplementary Note 10)

Preferably, the substrate processing apparatus may further include acontrol unit configured to control the source gas supply unit and thebarrier gas supply unit so as to supply an inert gas to the spacebetween the inner wall of the inner tube and the gas penetrationpreventing cylinder when a source gas is supplied to the inside of theinner tube.

(Supplementary Note 11)

Preferably, the substrate processing apparatus may further include acleaning gas supply unit configured to supply a cleaning gas to theinside of the inner tube through the gas nozzle.

(Supplementary Note 12)

Preferably, the substrate processing apparatus may further include acontrol unit configured to control the cleaning gas supply unit and thebarrier gas supply unit so as to supply an inert gas to the spacebetween the inner wall of the inner tube and the gas penetrationpreventing cylinder when a cleaning gas is supplied to the inside of theinner tube.

(Supplementary Note 13)

According to another preferred embodiment of the present invention,there is provided a method of manufacturing a semiconductor device, themethod including: loading a substrate holder into an inner tube, thesubstrate holder holding a plurality of substrates in a state where thesubstrate are horizontally oriented and stacked; forming thin films onthe substrates by supplying a source gas to an inside of the inner tube;and unloading the substrate holder from the inner tube, wherein theforming of the thin films is performed in a state where a region of thesubstrate holder lower than a region of the substrate holder where thesubstrates are stacked is enclosed by a gas penetration preventingcylinder.

(Supplementary Note 14)

Preferably, in the forming of the thin films, an inert gas may besupplied to a space between the inner tube and the gas penetrationpreventing cylinder.

(Supplementary Note 15)

Preferably, the forming of the thin films may include: supplying a firstsource gas to the inside of the inner tube; exhausting the first sourcegas from the inside of the inner tube; supplying a second source gas tothe inside of the inner tube; and exhausting the second source gas fromthe inside of the inner tube, wherein the supplying of the first sourcegas, the exhausting of the first source gas, the supplying of the secondsource gas, and the exhausting of the second source gas are grouped as acycle, and the cycle is repeated.

(Supplementary Note 16)

Preferably, the method may further include a cleaning operation whichincludes: supplying a cleaning gas to the inside of the inner tube wherethe substrate holder is loaded; substantially stopping exhaustion of theinside of the inner tube, and sealing the inner tube, in which thecleaning gas remains, for a predetermined time; and exhausting thecleaning gas from the inside of the inner tube, wherein the supplying ofthe cleaning gas, the stopping of the exhaustion, and the exhausting ofthe cleaning gas are grouped as a cycle, and the cycle is repeated.

(Supplementary Note 17)

Preferably, in the supplying of the cleaning gas, an inert gas may besupplied to the space between the inner tube and the gas penetrationpreventing cylinder.

What is claimed is:
 1. A method of manufacturing a semiconductor device,comprising: (a) loading a substrate holder into an inner tube, thesubstrate holder holding a plurality of substrates in a state where theplurality of substrates are horizontally oriented and stacked; (b)forming thin films on the plurality of substrates by supplying a sourcegas to an inside of the inner tube; and (c) unloading the substrateholder from the inner tube, wherein the step (b) is performed in a statewhere a conductance of a space between an inner wall of the inner tubeand a cylinder disposed under a region where the plurality of substratesare stacked is smaller than a conductance of the region where theplurality of substrates are stacked.
 2. A method of claim 1, wherein thethin films comprise high-k films.
 3. A method of manufacturing asemiconductor device, comprising: (a) loading a substrate holder into aninner tube, the substrate holder holding a plurality of substrates in astate where the plurality of substrates are horizontally oriented andstacked; (b) forming thin films on the plurality of substrates bysupplying a source gas to an inside of the inner tube; and (c) unloadingthe substrate holder from the inner tube, wherein the step (b) isperformed in a state where a distance between an outer edge of one ofthe plurality of substrates accommodated in the inner tube and a gasexhaust outlet is greater than a distance between the outer edge of theone of the plurality of substrates accommodated in the inner tube and agas injection hole.
 4. A method of claim 3, wherein the thin filmscomprise high-k films.
 5. A method of manufacturing a semiconductordevice, comprising: (a) loading a substrate holder into an inner tube,the substrate holder holding a plurality of substrates in a state wherethe plurality of substrates are horizontally oriented and stacked; (b)forming thin films on the plurality of substrates by supplying a sourcegas to an inside of the inner tube; and (c) unloading the substrateholder from the inner tube, wherein the step (b) is performed in a statewhere a distance between an upper end plate and a top plate of the innertube is shorter than a distance between a distance between twoneighboring substrates of the plurality of substrates.
 6. A method ofclaim 5, wherein the thin films comprise high-k films.
 7. A method ofmanufacturing a semiconductor device, comprising: (a) loading asubstrate holder into an inner tube, the substrate holder holding aplurality of substrates in a state where the plurality of substrates arehorizontally oriented and stacked; (b) forming thin films on theplurality of substrates by supplying a source gas to an inside of theinner tube; and (c) unloading the substrate holder from the inner tube,wherein the step (b) is performed in a state where a conductance of aspace between an inner wall of the inner tube and a cylinder disposedunder a region where the plurality of substrates are stacked is smallerthan a conductance of the region where the plurality of substrates arestacked, and in a state where a distance between an outer edge of one ofthe plurality of substrates accommodated in the inner tube and a gasexhaust outlet is greater than a distance between the outer edge of theone of the plurality of substrates accommodated in the inner tube and agas injection hole.